Enhanced Polymer-Polymer Blending and Polymer-Fiber/Particle Compounding Using Supercritical Carbon Dioxide

该项目将探索在基于单螺杆和双螺杆挤出工艺的先进聚合物和复合材料的混合和复合中使用超临界（致密气体）二氧化碳的潜力。二氧化碳是一种廉价、无毒、不受管制的溶剂。它不仅可以在传统的加工操作中取代液体有机溶剂，而且由于超临界状态下可用的独特性能，它可以在聚合物和复合材料工业中带来全新的制造工艺和产品。由于超过50%的商用聚合物是以共混或化合物的形式存在的，也许聚合物-聚合物共混和聚合物-纤维/颗粒复合的进步可以对聚合物加工产生最大的影响。超临界二氧化碳由于其良好的性质，目前在食品工业中得到了广泛的应用。围绕化学和塑料行业的监管环境为将超临界流体的一些成功应用到聚合物加工领域创造了机会。实验将研究超临界二氧化碳在各种聚合物中的溶解，以确定其对玻璃化转变温度、熔体粘度、链迁移率、密度和表面张力的影响。这些效应可用于改善聚合物和复合材料加工中的混合、润湿性和分子扩散。为了促进基础研究向应用的转化，该项目包括从新工艺概念到挤出机螺杆设计等多个层面的工业参与。研究人员将与工业咨询小组（包括材料供应商和挤出机制造商）密切合作，开发使用超临界二氧化碳的技术，以增强聚合物-聚合物、聚合物-纤维和聚合物-纳米颗粒在机械和反应性混合和复合中的混合。

This project will explore the potential of using supercritical (dense gas) carbon dioxide in the blending and compounding of advanced polymers and composites based on single and twin-screw extrusion processes. Carbon dioxide is an inexpensive, nontoxic, and unregulated solvent. Not only can it replace liquid organic solvents in conventional processing operations but, due to the unique properties available in the supercritical state, it can lead to completely new manufacturing processes and products in the polymer and composite industry. Since more than 50% of all commercial polymers are in the form of blends or compounds, perhaps the greatest impact on polymer processing can be achieved through advances in polymer-polymer blending and polymer-fiber/particle compounding. Supercritical carbon dioxide is currently being used extensively in the food industry due to its benign nature. The regulatory environment surrounding the chemical and plastic industries creates an opportunity to translate some of the successes of supercritical fluids to the polymer processing area. Experiments will investigate the dissolution of supercritical carbon dioxide into various polymers to establish the affect upon glass transition temperature, melt viscosity, chain mobility, density, and surface tension. These effects can be used to improve mixing, wettability, and molecular diffusion in polymer and composite processing. To facilitate the transfer of fundamental research into application, the project includes several levels of industrial involvement ranging from new process concepts to extruder screw design. The researchers will work closely with the industrial advisory group, including material suppliers and extruder makers, to develop techniques of using supercritical carbon dioxide to enhance polymer-polymer, polymer-fiber, and polymer-nanoparticle mixing in mechanical and reactive blending and compounding.